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Z Phase 1 Others > Week 10 > Flashcards

Week 10 Flashcards

1
Q

What are the two systems that the ear can be split into functionally?

A

Auditory and vestibular

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2
Q

What is the auditory system responsible for?

A

hearing

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3
Q

When does the auditory system begin?

A

As soon as sound waves enter the ear

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4
Q

What does the auditory system consist of?

A

The external, middle and inner ear

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5
Q

What is the external ear made up of?

A

The auricle (pinna) and the external acoustic meatus (auditory canal)

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6
Q

What are the auricles/pinnae made of?

A

They are composed of and shaped by elastic cartilage that is covered with skin

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7
Q

What is the function of the auricles/pinnae?

A

To direct sound into the external acoustic meatus

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8
Q

What are the three parts of the auricles/pinnae?

A

The helix, tragus and lobule

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9
Q

What is the external acoustic meatus?

A

An S-shaped passage that begins as an opening in the auricle

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10
Q

Where does the external acoustic media travel?

A

about 4 cm through the tympanic portion of the temporal bone to terminate at the tympanic membrane

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11
Q

What is The external acoustic meatus lined with?

A

mucous membrane containing sebaceous glands and modified sweat glands known as ceruminous glands

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12
Q

How is earwax (cerumen) formed?

A

when the secretions of ceruminous and the sebaceous glands combine

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13
Q

What is the function of earwax?

A

prevents the entrance of foreign particles into the ear and reduces the risk of bacterial and fungal infection

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14
Q

Where does the external acoustic meatus direct the sound waves to?

A

The tympanic membrane

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15
Q

what is contained in the middle ear?

A

The structures that amplify sound. these include the ossicles and auditory muscles

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16
Q

What is the tympanic membrane?

A

A thin, semi-transparent concave sheet.

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17
Q

What is the function of the tympanic membrane?

A
  • separates the external and middle ear
  • transmits vibrations from sound to the ossicles (malleus)
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18
Q

What is the tympanic cavity?

A

The cavity of the middle ear that contains the three ossicles

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19
Q

What is the tympanic cavity connected to?

A

The nasopharynx by the eustachian tube

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20
Q

What is the tensor tympani

A

a small muscle in the middle ear

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21
Q

Where is the tensor tympani?

A

it originates from the eustachian tube and sphenoid bone and inserts into the malleus

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22
Q

What is the function of the tensor tympani muscle?

A

To tense the tympanic membrane in response to abrupt noise and in anticipation to loud vocalization

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23
Q

What is the stapedius?

A

A small muscle in the middle ear

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24
Q

Where is the stapedius?

A

Attached to the temporal bone and the neck of the neck of the stapes

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25
Q

What is the function of the stapedius?

A

To dampen the vibrations of the ossicles by contracting in response to high intensity sound

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26
Q

What are the ossicles?

A

Three tiny bones found in the middle ear

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27
Q

What are the three ossicles?

A

The malleus, the incus and the stapes

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28
Q

What is the function of the ossicles?

A

They transmit and magnify sound from the tympanic membrane and across the tympanic cavity

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29
Q

What is the malleus?

A

largest and most lateral of the ossicles, It is attached to the tympanic membrane and articulates with the incus

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30
Q

What is the incus?

A

the middle ossicle and is located in the epitympanic recess of the tympanic cavity (middle ear) and it articulates with the stapes

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31
Q

What is the stapes?

A

the smallest and most medial ossicle of the middle ear. it articulates with the oval window of the inner ear

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32
Q

What is the function of the Eustachian tube?

A

-Connects the middle ear to the nasopharynx
-Allows the pressure within the cavity to remain equal to local barometric pressure

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33
Q

What is the oval window?

A

an opening between the middle and inner ear that articulates with the footplate of the stapes

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34
Q

What is the function of the oval window?

A

Allows the footplate of the stapes to transmit the sound vibrations from the middle ear to the inner ear

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35
Q

What is contained in the inner ear?

A

The sensory structures for both hearing and balance

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36
Q

What does the inner ear consist of?

A

A network of bony canals contained deep within the temporal bone

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37
Q

What are the parts of the bony labyrinth?

A

The cochlea and the semi-circular canals

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38
Q

How are the cochlea and semi-circular canals connected?

A

A centrally placed vestibule

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39
Q

What is the bony labyrinth?

A

a tube of bone that coils around a central pillar called the modiolus. It resembles a snail shell. Between the bony labyrinth and membranous labyrinth, sit two fluid-filled spaces: the scala vestibuli and scala tympani

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40
Q

What is the scala vestibuli?

A

A fluid filled space that passes the entire length of the cochlea.

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41
Q

What is the scala tympani?

A

A fluid filled space that passes through the entire length of the cochlea.

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42
Q

What is the fluid in the scala vestibuli and the scala tympani known as?

A

perilymph

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43
Q

What is perilymph maintained by?

A

The secretory epithelial cells that line the canals

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44
Q

What does the scala vestibuli connect to?

A

The oval window sits at the base of the canal, where it connects to the tympanic cavity.

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45
Q

What is the scala tympani connected to?

A

At its base sits the round window, which connects it to the tympanic cavity, and at its apex the helicotrema joins it to the scala vestibuli

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46
Q

What is the membranous labyrinth?

A

A coiled tube that contains the cochlear duct

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47
Q

What is the cochlear duct (scala media)?

A

The middle triangular canal that contains the organ of corti

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48
Q

What forms the roof and floor of the cochlear duct?

A

Roof - vestibular membrane
Floor - basilar membrane

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49
Q

What fluid does the cochlear duct contain?

A

Endolymph

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50
Q

What is the vestibule?

A

The central part of the bony labyrinth

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51
Q

What does the vestibule do?

A

connects the inner ear with the middle ear and has a supportive role

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52
Q

what does the vestibular membrane do?

A

Separates the cochlear duct from the scala vestibuli

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53
Q

What is the vestibular membrane?

A

a thin transparent membrane that stretches obliquely from the inner membrane of the modiolus

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54
Q

How does the vestibular membrane contribute to hearing?

A

When vibrations of the tympanic membrane are felt in response to sound waves, the pressure waves created are transmitted through the vestibular membrane to the basilar membrane

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55
Q

what does the basilar membrane do?

A

Supports the organ of corti and separates the cochlear duct (scala media) from the scala tympani

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56
Q

What is the structure of the basilar membrane like?

A

It is not uniform in width or thickness, as it is wider, thinner, and more pliant at the apex than at the base

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57
Q

What is the spiral ganglion?

A

The group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain

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58
Q

Where is the spiral ganglion found?

A

The modiolus. Fewer ganglion cells are found in the middle turn compared with the apical and basal turns

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59
Q

What is found within the spiral ganglion?

A

the cell bodies of the cochlear branch of the vestibulocochlear nerve (VIII)

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60
Q

What is the cochlear nerve?

A

A branch of the vestibulocochlear nerve (VIII)

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61
Q

Where do the nerve fibres of the cochlear nerve pass?

A

from the hair cells of the organ of Corti and through the modiolus as the spiral ganglia, before continuing onto the internal auditory meatus

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62
Q

What is the function of the hair cells on the organ of corti?

A

They act as sensor transducers

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63
Q

Where are the hair cells of the organ of corti found?

A

They rest on the basilar membrane with their stereocilia (hairs) embedded in the underside of the tectorial membrane.

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64
Q

What types of hair cell are there?

A

There are three or four rows of outer hair cells but only a single row of inner hair cells

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65
Q

What are stereocilia?

A

Membrane bound cellular projections of inner and outer hair cells

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66
Q

What is the role of the stereocilia?

A

they create a streaming movement in the surrounding fluid

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67
Q

where are the stereocilia found?

A

protrude from hair cells through the reticular membrane and point towards the tectorial membrane that lies above

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68
Q

How do the stereocilia contribute to hearing?

A

The bending movement causes them to depolarize and send information to the rest of the hair cell, turning the mechanical energy of a sound wave into a neural signal

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69
Q

What is the tectorial membrane?

A

a semi-transparent, fibro gelatinous structure that overlies the hair cells of the organ of Corti

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70
Q

What is the function of the tectorial membrane?

A

it withstands the mechanical stresses associated with cochlear fluid vibrations

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71
Q

What are the supporting cells of the organ of corti?

A

a series of specialized epithelial cells that provide mechanical support to the sensory cells that they surround.

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72
Q

what are sound waves?

A

oscillations of pressure in a medium, such as air or liquid

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73
Q

Where do external sound waves travel?

A

Through the external and middle ear to the auditory receptors in the cochlea

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74
Q

What is the pathway of sound in the external ear?

A

sound waves are directed by the auricle through the external acoustic meatus, to the tympanic membrane

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75
Q

What do the sound waves do to the tympanic membrane?

A

They cause it to vibrate

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76
Q

What does the tympanic membrane articulate with?

A

The ossicles

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77
Q

What happens when the tympanic membrane vibrates?

A

The ossicles transmit these vibrations to the cochlea

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78
Q

Where do the vibrations travel in the perilymph?

A

up the scala vestibuli and down the scala tympani

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79
Q

What happens when the vibrations arrive back at the round window?

A

it bulges out into the middle ear

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80
Q

Where is the cochlear duct?

A

Between the scala vestibuli and scala tympani

81
Q

What are the two branches of the vestibulocochlear nerve?

A

The vestibular and cochlear

82
Q

What parts of the ear are involved in balance?

A

The vestibule and semi-circular canals

83
Q

What does the vestibule contain that helps with balance?

A

Mechanoreceptors called maculae that detect static equilibrium

84
Q

What is static equilibrium?

A

The movements of the body relative to the forces of gravity

85
Q

What do the semi-circular canals contain that helps with balance?

A

mechanoreceptors called crista ampullaris that detect dynamic equilibrium

86
Q

What is dynamic equilibrium?

A

The angular movements of the body

87
Q

What is Acute otitis media?

A

A painful infection of the Middle ear

88
Q

What happens in Acute otitis media?

A

The middle ear becomes inflamed and infected

89
Q

What can cause Acute otitis media?

A

a primary or secondary bacterial infection or a virus

90
Q

What is a secondary bacterial infection?

A

Occurs after or because of a primary infection

91
Q

What happens if the swelling in the ear is too great?

A

the blood vessels in the ear drum are compressed, local tissue necrosis and the ear drum bursts, letting out pus and relieving the pain

92
Q

What is the standard treatment of Acute otitis media?

A

The prescription of an antibiotic even though 80%of all acute otitis media resolve spontaneously without treatment

93
Q

What happens if the inflammatory exudate causes the tympanic membrane to rupture?

A

The inflammatory exudate may spread to the mastoid air cells, causing acute mastoiditis

94
Q

What is serous otitis media?

A

When fluid accumulates in the middle ear as a consequence of eustachian tube obstruction

95
Q

What is another cause of serous otitis media?

A

It can also occur following otitis media, when the fluid in the ear, formed by the infection, does not drain spontaneously

96
Q

What does serous mean?

A

of, resembling, or producing serum

97
Q

What are the possible complications of serous otitis media?

A

risk for further infection and worsens hearing by about 30 dB

98
Q

How can serous otitis media be resolved?

A

by removing the obstruction e.g. in patients with tonsillar hyperplasia

99
Q

What is chronic otitis media?

A

persistent or repeated acute bacterial infections

100
Q

Why is there hearing loss if the tympanic membrane is perforated?

A

there is not enough area of the tympanic membrane to catch sound

101
Q

What are 4 common complications of chronic otitis media?

A
  • Tympanic perforation and discharge
  • Aural polyps: granulation tissue in the middle ear
  • Disarticulation and resorption of ossicles, with conductive hearing loss
  • Cholesteatoma
102
Q

What is Cholesteatoma?

A

accumulation of keratin derived from squamous epithelium spreading in from the external auditory canal following tympanic perforation

103
Q

What is labyrinthitis?

A

An infection of the inner ear/labyrinth

104
Q

What is the usual cause of labyrinthitis?

A

Virus

105
Q

Why are children more likely to get ear infections than adults?

A
  • their eustachian tubes are smaller and more level
  • Childrens immune systems aren’t as well developed as adults
  • Sometimes bacteria get trapped in the adenoids causing chronic infection that can pass to the ear
106
Q

What does the structure of children’s eustachian tube have to do with the increased likelihood of them getting an ear infection?

A

smaller and more level, which makes it difficult for fluid to drain out of the ear.

107
Q

What is thermoregulation?

A

a process that allows your body to maintain its core internal temperature

108
Q

What is the aim of all thermoregulation mechanisms?

A

to return your body to homeostasis

109
Q

How can muscles increase metabolic heat production?

A

They contract e.g. shivering

110
Q

What is non-shivering thermogenesis?

A

The breakdown of brown fat / brown adipose tissue

111
Q

Who has the most brown fat?

A

Babies - its prevalence decreases as humans age but there is still a small amount in adults

112
Q

What is vasoconstriction?

A

Shrinking the diameter of blood vessels that supply the skin

113
Q

What is vasodilation?

A

blood vessels get wider, or dilate, increasing blood flow to the skin

114
Q

What is counter-current heat exchange?

A

a circulatory adaptation that allows heat to be transferred from blood vessels containing warmer blood to those containing cooler blood

115
Q

How does counter-current heat exchange work?

A

As warm blood passes down the arteries, the blood gives up some of its heat to the colder blood returning from the extremities in these veins.

116
Q

What are the four ways heat can be lost?

A

convection, conduction, radiation, and evaporation

117
Q

What happens in hot conditions?

A

-Eccrine sweat glands under the skin secrete sweat
-The hair on the skin lie flat, preventing heat from being trapped by the layer of still air between the hair
-Arteriolar vasodilation, redirecting blood into the superficial capillaries in the skin increasing heat loss by convection and conduction

118
Q

What happens in cold conditions?

A

-Sweat production is decreased
-hair erector muscles contract causing a layer of air to be trapped, insulating the skin
-arteriolar vasoconstriction
-shivering and muscle contraction to generate heat
- non-shivering heat production through brown adipose tissue

119
Q

What is thermogenin?

A

The uncoupling protein used to generate heat by non-shivering thermogenesis

120
Q

Where is thermogenin found?

A

The mitochondria of brown adipose tissue

121
Q

What is a fever?

A

having a temperature above the normal range

122
Q

What are pyrogens?

A

Chemicals in the bloodstream that cause fevers

123
Q

What are fevers caused by?

A

Pyrogens

124
Q

What are the two types of pyrogens?

A

Endogenous and exogenous

125
Q

What is an endogenous pyrogen?

A

Internal

126
Q

What is an exogenous pyrogen?

A

external

127
Q

What is a common example of a pyrogen?

A

Interleukin-1 (IL-1)

128
Q

What are most endogenous pyrogens?

A

Cytokines

129
Q

How is IL-1 produced?

A

By macrophages when they come into contact with certain bacteria and viruses

130
Q

What do pyrogens cause the release of?

A

Prostaglandin E2 (PGE2)

131
Q

What does PGE2 do?

A

acts on the hypothalamus, which creates a systemic response in the body causing heat-generation effects to match a new higher temperature set point.

132
Q

What is the ultimate mediator of the fever?

A

PGE2. The set point temperature of the body will remain elevated until PGE2 is no longer present.

133
Q

What does the hypothalamus act as?

A

A thermostat

134
Q

What causes the hypothalamus to change set point?

A

Prostaglandins

135
Q

What is thought to be the purpose of a fever?

A

to raise the body’s temperature enough to kill off certain bacteria and viruses sensitive to temperature changes

136
Q

What does the increase in set point trigger?

A

increased muscle contractions and a feeling of cold

137
Q

Why does paracetamol not work as an anti-inflammatory?

A

It does not appear to inhibit the function of any cyclooxygenase (COX) enzyme which is what NSAIDs such as aspirin do

138
Q

How does paracetamol work?

A

It appears to inhibit COX in the brain selectively

139
Q

How does paracetamol inhibit COX?

A

This does not appear to be by direct inhibition (by blocking an active site), but by reducing COX which must be oxidised in order to function.

140
Q

How is paracetamol thought to relieve pain?

A

by reducing the production of prostaglandins in the brain and spinal cord, increasing our pain threshold

141
Q

When are prostaglandins produced?

A

by the body in response to injury and certain diseases

142
Q

What is one of prostaglandins actions?

A

to sensitise nerve endings, so that when the injury is stimulated it causes pain

143
Q

How does paracetamol work on a fever?

A

It acts as an antipyretic and reduces fever by promoting heat loss and thus helps reset the hypothalamic thermostat

144
Q

Describe the blood supply to the kidney

A

renal artery divides into segmental arteries, which then divide to become lobar arteries. Between the medullary pyramids they branch to become interlobular arteries. These extend towards the cortex then arch round the bases of the medullary pyramids to form the arcuate arteries. From the arcuate arteries, interlobular arteries penetrate the cortex. Branches of the interlobular arteries called afferent arterioles carry blood directly into nephrons

145
Q

What is the normal intake of fluids in an adult?

A

about 1200ml water
1000ml food
metabolic 300ml
total about 2.5 litres

146
Q

What is the normal fluid output for adults?

A

urine about 1500ml
sweat about 100ml
faeces about 200ml
insensible loss about 700ml
total about 2.5 litres

147
Q

describe the sequence of blood vessels in the kidney

A

afferent arteriole
glomerular capillary
efferent arteriole
tubular capillary
venule

148
Q

How many nephrons are there?

A

10 to the power of 6

149
Q

what are the 2 types of nephron ?

A

junta-meduallry
superficial

150
Q

Describe a nephron

A

each nephron is a tube
the nephron wall is a continuous layer of epithelium
the cell shapes in the wall are very different
this reflects activity; surface area, ion pumping etc

151
Q

What is meant by ultrafiltration?

A

driven by blood pressure
high renal blood flow
high filtration rate

152
Q

what is meant by reabsorption?

A

active pumping from filtrate into tubules
water, glucose, amino acids, electrolytes etc

153
Q

What is meant by secretion?

A

active pumping into tubules
for substances to be eliminated faster than filtration alone allows

154
Q

what are pumping rates controlled by?

A

hormones

155
Q

Describe glomerulus ultrafiltration

A

high glomerular capillary pressure
filtration of small molecules through slits between podocytes (ions, water, glucose, amino acids etc)
limit is space between posocyte processes
filtration rate 90-140ml/min

156
Q

Describe what happens at the proximal convoluted tubule

A

active reabsorption
brush border
active reabsorption of glucose, Na+, K+ ions
Co transporters, aqueous channels, membrane pumps
Substantial water reabsorption

157
Q

What has occurred by the end of the PCT?

A

complete reabsorption of glucose, amino acids
Substantial reabsorption of Na+, water
volume filtrate reduced by 2/3

158
Q

Describe what happens at the loop of Henle

A

counter-current concentration
thinner wall during descent into medulla
thicker wall during ascent -active pumping out of tubule
solute diffuses into descending tubule;
countercurrent mechanism “recycles” solutes
ion pumping develops high osmotic pressures at the tip of the loop
no net reabsorption here

159
Q

Describe what happens at the distal convoluted tubule

A

more solute reabsorption and secretion
similar structure and function to proximal tubule
no need for glucose transported
less intense electrolyte and water reabsorption
DCT ion pumping can be controlled by hormones like aldosterone to “fine tune” Na+ and K+ exchange

160
Q

describe what happens at the collecting duct

A

concentration of urine
if CDs are permeable to water it may be drawn out by the high osmotic pressure present at the tip of the loop of Henle
Duct permeability set by ADH
if ADH is present aquaporins are inserted into the luminal membrane to allow water movement

161
Q

Describe the kidneys control of the blood pressure

A

hypofiltration and sympathetic stimulation initiates secretion of renin by the juxtaglomerular apparatus
renin converts angiotensinogen to angiotensin II which is a powerful vasoconstrictor

162
Q

Describe the kidneys control of salt balance

A

When electrolyte concentrations fall aldosterone is produced by the glomerulosa cells of the adrenal cortex
This increases the reabsorption of Na+, CL- and therefore water
It increases the secretion of K+ ions

163
Q

Describe the pathophysiology of benign prostate hyperplasia

A

BPH is a benign increase in the size of the prostate
hyperplasia of prostate stromal and epithelial cells in the transition zone of the prostate
may impinge on the urethra and increase resistance in the flow of urine from the bladder
increased likelihood of urinary tract infections

164
Q

What is the pathophysiology of BPH?

A

benign prostatic hyperplasia
BPH is a benign increase in size of prostate stromal and epithelial cells in the transition zone of the prostate
May impinge on the urethra and increase resistance in flow of urine from the bladder

165
Q

Describe PSA screening and why it is not used in the UK

A

prostate specific antigen screening
PSA tests are unreliable and can suggest prostate cancer where there is none
20% of men with prostate cancer don’t have elevated PSA
PSA testing alone can’t determine whether symptoms are due to BPH or prostate cancer because both conditions can elevate PSA levels

166
Q

What is screening?

A

a strategy used in a population to identify unrecognised disease in individuals without signs or symptoms
performed on individuals in apparently good health

167
Q

What are the conditions of screening?

A

Condition should be important health problem
there should be a treatment for the condition
facilities for diagnosis and treatment should be available
there should be a latent stage of the disease
the should be a test of examination for the condition
the test should be acceptable to the population
the natural history of the disease should be known
there should be an agreed policy on who to treat
the total cost of finding a case should be economically balanced in relation to medical expenditure as a whole
case finding should be a continuous process

168
Q

Outline bowel screening

A

all men and women aged 50-74 every 2 years

169
Q

Outline breast screening

A

mammography women aged 50-70 every 3 years

170
Q

Outline cervical screening

A

women aged 25-65
3 yearly intervals to 50 then 5 years to 65

171
Q

Describe cervical screening

A

cervical cancer proceeded by pre-invasive stage CIN
(Cervical intra-epithelial neoplasia)
Abnormal cells detected in cervical smear
CIN can be treated by directed focal treatment at colposcopy

172
Q

What are some risk factors for cervical cancer?

A

sexually transmitted disease
HPV
cigarette smoking
early age of first sexual intercourse
type of contraceptive used
social depravation
immunosuppression

173
Q

what are the two main types of drug?

A

small molecules
biologics

174
Q

What is drug action mediated by?

A

the time course of the drug concentration at the site of action

175
Q

Describe drug receptors

A

a macromolecular component of a cell with which a drug interacts to produce a response

176
Q

Describe how drugs act of receptors

A

on cell surface or inside cell
form tight bonds with the receptor
drug needs to meet certain requirements (size, shape)
the drug can stimulate or inhibit the receptor action
this usually involves an effect on a signal transduction pathway / alters enzyme function

177
Q

Give examples of types of drug receptor

A

enzyme linked (multiple actions)
ion channel linked (speedy)
G protein linked (amplifier)
Nuclear (gene) linked (long lasting)

178
Q

what is affinity?

A

measure of propensity go a drug to bind to a receptor

179
Q

what is efficacy?

A

also called intrinsic activity
ability of a bound drug to change the receptor in a way that produces an effect; some drugs possess affinity but not efficacy

180
Q

Describe antagonists and agonists

A

agonists have affinity and intrinsic activity
antagonists have affinity but no intrinsic activity
partial agonists have affinity but less intrinsic activity
competitive antagonists may be overcome

181
Q

Describe competitive antagonists

A

competes with agonist for receptor
surmountable with increasing agonist concentration
reduces apparent affinity of agonist

182
Q

Describe non-competitive antagonists

A

Drug binds to receptor and stays bound
Irreversible - does not let go of receptor
as more receptors are bound, the agonist becomes incapable of eliciting maximum effect.

183
Q

What is meant by ED50?

A

median effective dose 50
the dose at which 50% of sample or population manifest a given effect

184
Q

What is meant by TD50?

A

median toxic dose 50
the dose at which 50% of the populations manifests a given toxic effect

185
Q

What is meant by LD50?

A

median lethal dose 50
dose which kills 50% of subjects

186
Q

What is therapeutic index?

A

`TD50 or LD50 / ED50
the higher the therapeutic index the better

187
Q

What is the minimum urine production rate?

A

1ml/min

188
Q

what is the maximum urine production rate?

A

20ml/mon

189
Q

Describe the bladder structure

A

bladder wall; smooth muscle (detrussor)
smooth muscle allows large volume changes
the activity of the depressor muscle is affected by reflexes, stretch of the wall ringers contractions

190
Q

Describe the storage phase

A

early filling phase; low pressure in bladder, bladder wall and eternal sphincter relaxed
no flow in urethra; urethral pressure > bladder pressure
sensations develop, the sphincters contract to maintain continence

191
Q

Describe the voiding phase

A

“urge” then voluntary voiding
bladder contracts, urethra and sphincter relax

192
Q

What type of muscle is the external sphincter?

A

skeletal

193
Q

Describe the innervation of the bladder and sphincter

A

Sympathetic L1, L2- bladder wall and internal sphincter
Parasympathetic S2,3,4 bladder wall
Somatic S2,3,4 sensory and motor to external sphincter

194
Q

Describe the afferent innervation of bladder control

A

sensory fibres sense the stretch in the bladder wall
these afferents run in the hypogastric nerve and end the cord in the upper lumbar roots
Other sensors near the urethra sense flow of urine
skeletal muscle sensors in external sphincter

195
Q

Describe efferent innervation of bladder control

A

Parasympathetic to depressor
sympathetic to internal sphincter
Somatic to external sphincter

196
Q

Describe innervation during the storage phase

A

sympathetic effects dominate
adrenergic Bera effects - suppress contraction of detrussoe
Somatic fibres in the pudendal nerve control external sphincter

197
Q

Describe the innervation during the voiding phase

A

parasympathetic actions dominate
parasympathetic fibres in the pelvic splanchnic nerve cause the depressor to contract

198
Q

Describe reflex control of the bladder

A

via the centres in the sacral cord and in the pons
Pontine centre coordinates with higher centres

Z Phase 1 Others (11 decks)

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